OptoForce Force Sensing Systems

Quadratec Ltd are the UK & Ireland technical distributors for an advanced technology range of unique optical sensing instrumentation produced by OptoForce Ltd, based in Budapest, Hungary (http://optoforce.com).

OptoForce offers unique multi-axial force/torque sensors with a revolutionary optical technology that equips industrial robots with the sense of touch, providing the tactile sensing of automated equipment and haptic interaction between people and robots.

Example of a 6-Axis Force/Torque Sensor attached to a Universal Robot arm

OptoForce Solutions and Applications

Some typical areas of application and processes are shown in the table below:

Applications	Processes	HEX-E or HEX-H
Assembly	Car engine, electronics, screw pre-feeding, small parts	HEX-E
Surface Finishing	Sanding, metal and plastic polishing, deburring, grinding	HEX-H
Handling	Palletising, stacking and de-stacking	HEX-H
Insertion of Objects	Part snapping, pin insertion, battery insertion, connector insertion	HEX-E
Hand-guide/Path recording	Teleoperation, presence detection, arc welding, any processes involving complex shapes	HEX-E/HEX-H
Testing	Connector, automotive parts, button clicking, weight measurements	HEX-E

Sensor Compatibility and Packages

Plug and Play packages come with sensor hardware and a range of prior developed application programmes specific to the manufacturer's robot, designed to make the interaction and set up easy for the user, with an easy to use graphical interface to the existing robot pendant. These packages are currently available for "Universal Robots" and "Kuka" robots, whilst continued efforts are ongoing to extend that range of availability to manufacturers such as ABB and Yaskawa.

Outside of the currently available Plug and Play options the sensors can be mounted to many other different manufacturers' robots/cobots (such as ABB and Yaskawa). Ethernet is a common option for communication between the robot and an OptoForce controller (Compute Box) this helps with the data acquisition, data transfer and the overall communication between the robots controller and the sensor. An API (Application programming interface) is another option for easy communication with different types of robots which use various types of programming languages.

OptoForce Sensing Technology

In optical force sensors, photodiodes are used to measure the amount of reflected light originally emitted by an LED. By comparing the measured values on each photodiode the acting forces can be precisely reconstructed - and not just their magnitude, but also their direction.

Optoforce Sensing Technologies

An example of a single 3-axis optical force sensor, typically 3 of these sensors will be used in the construction of a 6-axis force/torque sensor assembly.

Sensor Technology Comparison

Compared to strain-gauge based load cells, OptoForce sensors are generally much more robust, as the deforming surfaces are physically separated from the sensing element. This is achieved by utilizing infrared light to detect the smallest deformation in the shape of the outer surface and incorporating different kinds of optical grade elastomers to achieve the most reliable results.

OptoForce Sensor Types

There are two variants of the force/torque sensor aimed at different levels of applied forces, both having the same exterior appearance:

HEX-E Sensor
Ideal for applications utilising light weight tools, where the application itself requires a very minimum/low force. Examples of such applications can be viewed within the selection of videos on the right side of the page.
HEX-H Sensor
Ideal for those applications that demand higher loads, providing improved accuracy due to lower deformation of the elastomer. Examples of such applications can be viewed within the selection of videos on the right side of the page.

Side-On View of the HEX Sensor